1. Field of the Invention
The disclosed invention relates to an arrangement of power and control signal rails through which power and control signals are carried to transportation vehicles operating on the roadway of a transportation system.
2. Description of the Prior Art
Transportation systems employing at least one self-propelled, rubber tire vehicle which traverses a roadway comprises of laterally spaced, parallel tracks are well known in the prior art and generally described in "Transit Expressway Report" of the MPC Corporation, 4400 Fifth Ave., Pittsburg, Penna. 15213, dated Feb. 20, 1967 and in U.S. Pat. No. 3,312,180 of E. O. Mueller. In these prior art transportation systems, the vehicles were directed along the roadway by guide wheels depending from the bottom of each vehicle and traveling a guide beam supported parallel to the roadway tracks. Also in these transportation systems, electric power was supplied to the vehicle through current collectors in contact with power rails mounted in relation to the guide beam or to the roadway tracks. Control signals were supplied to the vehicle through antennas mounted on the roadway by adhesives.
In one power rail mounting arrangement known in the prior art, power rails were mounted in insulative brackets fixed to the roadway tracks such that the rail surfaces in contact with the collectors were in a horizontal plane. However, this prior art arrangement for mounting power rails on transportation system roadways required extensive adjustment at the installation site to obtain proper alignment between the rails and the collectors mounted on the vehicle, making this arrangement expensive and difficult to implement. In addition, since this arrangement could not provide power to a vehicle traveling through roadway switching areas, it required additional sets of power rails and complementary collectors at the roadway switching areas.
A second power rail arrangement known in the prior art provided for bracketing the power rails to a lower flange of the guide beam such that the rail surfaces in contact with the collectors were located below the horizontal plane of the vehicle guide wheels. Since this arrangement would allow the guide wheels to pass over the power rails, power could be provided to the vehicle as it traveled through the roadway switching areas. However, since the power rails were also located close to the roadbed, this arrangement was susceptible to accumulations of dirt and moisture on the collection surfaces of the rails.
Both of these prior art arrangements permitted lateral or rolling forces acting on the vehicle to interfere with the contact between the collectors and the rails and, for transportation systems with vehicle turn-around capability, required multiple sets of power rails, power collectors and control signal receivers. Also, since the power rails of the prior art arrangements were laterally disposed, reactive interference between power rails carrying a multiple phase alternating power signal limited the efficiency of the signal rail arrangements of the prior art.
Therefore, there was a need for a new power and control signal rail arrangement which could be installed without extensive adjustments; which would provide power and control signals to a vehicle in roadway switching areas; and which would be resistant to interference from dirt and moisture. The new rail arrangement should also be less susceptible to interference with collector-rail contact caused by lateral or rolling forces acting on the vehicle; reduce the reactive interference between power rails; and provide turn-around capability with a single set of power and control signal rails.